Honda S65

Some success and still some head scratching.

Took the carb apart again and blew out both jets. I noticed a little bit of crud in the jets and in e fuel I drained out of the carb. I think the crud is from either the old gaskets or the coating on the float.

I also took the carb screws all the way out and cleaned everything. Now I need to adjust the carb. Not exactly sure what I'm doing, but the the exhaust isn't blue and it'll idle more or less indefinitely. No road test yet because now if you give it some throttle, it doesn't want to snap back to closed.

In reply to LainfordExpress: Not snapping back, is a separate issue I think. Sounds like the cable maybe worn out inside. Take the cable loose and get some cable lube or oil into it. One way to do this is to take a ziplock back, poke the cable through one corner. Hang the bag with cable hanging down. Duct tape the cable/bag intersection to seal it. Pour oil in bag and it will run into the cable (bag acts as funnel).

I agree that the throttle issue is unrelated to the carb.

I want to get the carb adjusted, then mess with the throttle cable. To adjust, I bottomed out both screws, then backed them out two turns, and tried to start it. Once it started, It reved to the moon, so I kept backing out the throttle screw until it was reasonable, but the exhaust was blue. So I slowly backed out the air screw (increasing airflow?) and then pushing in the throttle cable (more fuel) until it sorta sounded right.

What I can figure out is this: There will be an ideal balance between air and fuel... But that could be at any setting. I mean, I could max out the air, and then adjust the throttle, or vice-versa, but that probably isn't "best". How do I figure out what the ideal is for one screw, and then adjust the other one to it's ideal that matches?

I'm not writing this very well... There is some relationship between these two adjustments, let's say they are intersecting lines. I need to move their intersection to the ideal spot, but there has to be a better way than just turning screws back and forth until it sounds right, correct?

This is where it get very methodical. If it were me I would take care of any variables that affect the performance of fuel delivery (throttle cable etc.). Carbs this small are very sensitive. You may get/think you have it all tuned and then a new cable will allow the carb to move more freely and affect things. Then you would have start over. This reminds me of my days dialing in Weber DCOE's. I learned a lot from those days. The biggest thing I learned is to be methodical and clean. One step at a time. Take notes so that you can go back to the previous step and undo. At this point you can't go by the color of exhaust smoke. There could be multiple reasons that your smoke is x color. Bad rings etc. The way to tell if the mixture is right is to get it running well. Get a clean plug. Run the engine then shut the engine off. Check the plug's insulation's color. Chocolate is good. Black and cakey is too rich. Blistered and white is too lean. Black and shiny with build up = bad rings (oil in combustion chamber). Advice. Don't short cut. You have to be like a dr. on this, eliminating one issue at a time and literally crossing it off you list.

Firstly, the petcock is not part of the carb on the S65. It is a very typical Honda petcock that is bolted to the bottom of the fuel tank. You can see it in this photo, just below the knee pad:

And the choke is the kind that moves a plate down in front of the air intake stream. Not the kinda with a fuel enrichment circuit.

In reply to subrew:

that is nice looking

Mine is Championship White, but quite a bit rougher looking.

So I have it running decently now, but to get there, when I adjusted the air screw on the carb, I never really got a high idle, it just kept going up until it bottomed out. I checked the spark plug, and it looked grayish, not black or white, but still that seems weird. It still doesn't exactly want to idle that well, especially when it's been running for an hour.